Power manager is asking for authentication to perform automatic suspend.

When idle for the suspend-time, i find the login window, then log in, then i see this window:
“Authentication is required to place the system in suspend or hibernate mode
An aplication is attempting to perform an action that requires privileges.
Authentication as one of the users below is required to perform this action.”

if i give the password, then it suspends.

Obviously, this means i have no power saving at all (only screensaver works). The system won't never suspend by itself.

I'm running LM 18.3 xfce. I have never had this authentication issue on earlier releases,

Another issue related to Power Manager: Sometimes, suspend shortcut (XF86Sleep) stops working. If i restart session, it works again.

With this settings automatic suspend works ok at the expected time (2΅)

So, there must be something with the dpms, screen saving/ locker.
I find there is a strange behaviour with screen saving when enabled
If i set this
a) dpms:
-blank: 1 minute
-sleep: 2 minutes
-off: 3 minutes

at the expected blank time, the screen of my laptop turns off (or blanks, i can't tell the difference between them).
Then, 15 seconds later the screen turns on at the login screen of lightdm. This is the locker effect. But why turn on the screen? Then the screen remains on for about 10 minutes from the blank time (11 minutes after idle) and then turns off again.
The suspend time is apparently ignored.
Notice that this "10 minutes" value is not set anywhere at the xfce4-power-manager. It comes from somewhere else.
No suspend at all.

Then, if i press any key. and enter password at the login screen, the screen unlocks and i get the window asking for password to suspend (or cancel)

so, it seems the problem is when the locker activates. But i'm not sure.

EDIT 2:
I think i found the correct settings:
On Power Manager > Security tab, I set Light locker to Automatically lock the session: When the screensaver is deactivated

That solves the problem. Screen saving and System power saving work as expected now.
Thank you.